1. Field of the Invention
The present invention relates to a thermal printer, a thermal printing method and a conveyor for recording material. More particularly, the present invention relates to a thermal printer which can be easily combined with a personal computer, a video player or the like, and a thermal printing method and a conveyor for recording material used with the thermal printer.
2. Description Related to the Prior Art
A tower type of personal computer has been recently used widely. The personal computer of this type has a feature of high extensibility, and includes a plurality of so-called bays, or spaces for setting respective relevant devices such as a flexible disk (FD) drive device, a hard disk device, a compact disk (CD) drive device and an MO drive device. Each bay can contain such a peripheral unit which is approximately 146 mm wide, 41 mm high, and 220 mm deep.
There is another suggestion of the personal computer in which a scanner is set in the bay with intention of extension, the scanner previously having been connected externally to a computer in a conventional manner. With the scanner or other peripheral units incorporated in the body of the personal computer, convenience and ease in use of them is increased. There is no need of externally connecting operation. Furthermore peripheral units to be installed do not require installing spaces in a room, although such are still required by external peripheral units.
It is conceived to combine a color printer with the personal computer of the tower type as one of the peripheral units, because the color printer will be usable with high frequency and much convenience. However there is no color printer which could be mounted in the bay of the personal computer, because the color printer in the prior art is too large and cannot be constructed in a small size suitable to the bay.
There is a color thermal printer of a sublimation type or wax transfer type, which is used with ink ribbon. The ink ribbon is wound in a roll form, which inevitably has a size of 25-30 mm at the minimum. It is impossible to construct the printer with a thickness equal to or less than 41 mm. Moreover the ink ribbon, when used up, must be renewed. If the bay contained the color thermal printer of this type, the entirety of the printer must be pulled out and opened for the purpose of renewal of the ink ribbon.
There is no ink jet printer which would be mounted in the bay of the personal computer, because sizes of an ink tank and a recording head of an ink jet printer cannot be reduced and are inconsistent to the smallness of the bay. The ink jet printer has a mechanical system of a serial printer, and also requires a mechanism for moving the recording head. Also the ink jet printer must be supplied with ink periodically. A body of the ink jet printer must be drawn and opened before the ink can be supplied. Both the head moving mechanism and supply of ink cause problems in failure of obtaining compactness of the body.
Among various types of color printers, there is a color thermal printer in which color thermosensitive recording material of direct thermal recording is heated to develop color by itself. The color thermal printer does not use ink ribbon, ink or other expendable material, and does not need to be open for the purpose of supplying anything expendable. Therefore this type of the color thermal printer has suitability to being contained in the bay of the personal computer.
The recording material includes a support, and a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer, and a yellow thermosensitive coloring layer, all of which are overlaid on the support. Among the three layers, the yellow coloring layer, which lies the farthest from the support, has the highest heat sensitivity. In the color thermal printer, a thermal head is pressed against the recording material, to print a yellow image to the yellow coloring layer line by line at first. Then a yellow fixer applies ultraviolet rays to the yellow coloring layer to fix the yellow image. The thermal head prints a magenta image to the magenta coloring layer next. A magenta fixer applies ultraviolet rays to the magenta coloring layer to fix the magenta image. Finally the thermal head prints a cyan image to the cyan coloring layer, so as to obtain a full-color image.
The thermal recording and the fixation are effected while the recording material is conveyed in a manner relative to the thermal head and the fixer unit. An example of various structures for conveying the recording material is a back-and-forth moving structure. The color thermal printer with this structure includes a recording material conveyor device or a conveyor roller set, which is constituted by a capstan roller and a pinch roller. The capstan roller is driven by a motor to rotate. The pinch roller has a diameter smaller than that of the capstan roller. The conveyor roller set nips the recording material and conveys it back and forth, while the thermal head pressurizes and heats the recording material to develop the three colors sequentially, that are yellow, magenta and cyan.
However there is no known color thermal printer which would be mounted in the bay of the personal computer, because of considerable largeness of parts and components in a color thermal printer and a large space required for their arrangement. For the three coloring layers, temperature at which each coloring layer starts being colored is different. Therefore the color thermal printer of the direct recording type inevitably has the maximum heating temperature higher than that of a wax transfer type of thermal printer, in which the temperature at which each coloring layer starts being colored is equal between the coloring layers. In the direct recording type, generated heat is considerably much due to the heating temperature. The problem of considerable generated heat should be solved in mounting the color thermal printer in the bay of the personal computer, in addition to the dimensional problems of the color thermal printer and its parts.
In view of the foregoing problems, an object of the present invention is to provide a thermal printer having a sufficiently small size and easily combined with a personal computer, a video player or the like, and a thermal printing method and a conveyor for recording material used with the thermal printer.
Another object of the present invention is to provide a thermal printer in which generated heat can be removed in an effective manner, and a thermal printing method and a conveyor for recording material used with the thermal printer.
Still another object of the present invention is to provide a thermal printer in which a fixer lamp can be easily removed and secured inside a printer casing, and a thermal printing method and a conveyor for recording material used with the thermal printer.
Another object of the present invention is to provide a thermal printer in which ranges of two margins upstream and downstream from a printing area on a recording material can be determined in an apparently suitable manner, and a thermal printing method and a conveyor for recording material used with the thermal printer.
A further object of the present invention is to provide a thermal printer capable of reducing influence of ambient light to a recording material being optically fixable, to protect its coloring ability of coloring layers, and a thermal printing method and a conveyor for recording material used with the thermal printer.
Another object of the present invention is to provide a thermal printer in which structural failure in a recording material conveyor is avoided, to prevent failure in registering the three colors and irregularity in conveying the recording sheet, and a thermal printing method and the conveyor for recording material used with the thermal printer.
In order to achieve the above and other objects and advantages of this invention, a thermal printer for recording an image to thermosensitive recording material, includes a conveyor for conveying the recording material along a conveying path, a thermal head for thermally recording the image to the recording material being conveyed, and a fixer lamp for applying electromagnetic rays of a predetermined range of wavelength to the recording material being conveyed, for optically fixing the recording material. In the thermal printer, a printer casing has a box shape of which a height is small, and includes a front face oriented substantially vertically to a direction of the height, and a rear face opposite to the front face. An insertion opening is formed in the front face, and adapted to insertion of the recording material therethrough before the recording, and ejection of the recording material therethrough after the recording. An air inlet and an air outlet are formed in the front face, the insertion opening being disposed between the air inlet and the air outlet. An air passageway is disposed in the printer casing, for communicating from the air inlet to the air outlet via at least a portion of the conveying path. A fan unit is disposed in the air passageway, for causing air from the air inlet to flow along the air passageway, to cause heat generated in the printer casing to exit from the air outlet.
Moreover, a partition is disposed to extend along the conveying path, for defining first and second portions of the air passageway on respective sides thereof by partitioning an inside of the printer casing, the first portion extending from the air inlet, and the second portion communicating with the first portion at an edge of the partition, and extending to the air outlet.
Consequently in the thermal printer, generated heat can be removed in an effective manner. The thermal printer can have a sufficiently small size and easily combined with a personal computer, a video player or the like.
In a preferred embodiment, a driver circuit drives the fixer lamp. There is a printed circuit board on which the driver circuit is mounted, and to which the fixer lamp is secured.
Consequently the fixer lamp can be easily removed and secured inside a printer casing.
In another preferred embodiment, a conveyor roller set includes first and second rollers, for nipping the recording material and for rotating, to convey the recording material along a conveying path in a first direction and a second direction reverse to the first direction. A fixer unit emits electromagnetic rays to fix the recording material while the recording material is conveyed, wherein the first roller is disposed between the fixer unit and the recording material, and the fixer unit applies the electromagnetic rays to the recording material through upstream and downstream spaces adjacent to the first roller.
Consequently ranges of two margins upstream and downstream from a printing area on a recording material can be determined in an apparently suitable manner.
In still another preferred embodiment, the recording material includes a support, and at least first, second and third thermosensitive coloring layers, overlaid on the support, for developing respective colors being different from one another, wherein the first coloring layer is disposed at a recording surface, the third coloring layer is disposed most deeply from the recording surface, and the first and second coloring layers have fixability to electromagnetic rays of respectively first and second ranges of wavelength. The thermal printer includes a printer casing. A conveyor is disposed in the printer casing, for conveying the recording material along a conveying path. A thermal head is disposed under the conveying path, confronted with the recording surface of the recording material directed downwards, for heating the at least first, second and third coloring layers serially to develop the colors while the recording material is conveyed, for effecting thermal recording of the full-color image in a frame-sequential manner. A fixer is disposed under the conveying path, confronted with the recording surface, for emitting electromagnetic rays of first and second ranges of wavelength, to fix the first and second coloring layers optically.
Consequently the thermal printer is capable of reducing influence of ambient light to a recording material being optically fixable, to protect its coloring ability of coloring layers.
In another preferred embodiment, a recording material conveyor device for conveying recording material, includes a motor. A capstan roller is rotated by the motor. A rotatable pinch roller is disposed in a manner confronted with the capstan roller, for nipping the recording material between the pinch roller and the capstan roller. A pinch roller supporter supports the pinch roller in a shiftable manner in a direction crosswise to a rotational axis of the pinch roller, wherein the pinch roller, before nipping the recording material, is set in a first position with a smaller distance to the capstan roller than a thickness of the recording material, and when nipping the recording material, is set back from the first position.
Consequently structural failure in a recording material conveyor is avoided, to prevent failure in registering the three colors and irregularity in conveying the recording sheet.